The present invention relates to an ink jet recording device, in which the ink jet recording device includes an ink jet recording head which is mounted on a carriage and ejects ink drops in accordance with print data, and a capping unit which seals and covers a nozzle forming surface of the recording head and receives a negative pressure from a suction pump to suck ink from the recording head and to discharge the ink outside. More particularly, the invention relates to an ink jet recording device in which a wiping member is mounted on the capping unit, and is brought into sliding contact with the nozzle forming surface of the recording head to wipe the nozzle forming surface, and a method for driving and controlling the ink jet recording device.
Generally, the ink jet recording device includes an ink jet recording head which receives ink from an ink cartridge, and a sheet feeding unit for moving a recording sheet of paper relative to the recording head. The recording device records an image pattern on the recording sheet in accordance with print data, while moving the recording head. A recording head, which is able to eject color inks of colors, such as black, yellow, cyan and magenta color inks, is mounted on a carriage. With use such a recording head, the ink jet recording device is capable of performing the full color printing as well as the text printing by varying a ratio of the color inks to be ejected.
To print by the recording head, ink is pressurized in a pressure generating chamber, and ejected through the nozzle opening of the head in the form of ink droplets onto the recording sheet. For this reason, the recording head has a possibility of causing a printing failure due to trouble regarding ink ejecting effect from the nozzle opening, such as an increase of ink viscosity or solidification of ink due to evaporation of solvent contained in the ink from the nozzle openings, the attaching of dust, and the entering of air bubbles into the head.
To cope with this, this type of ink jet recording device includes a capping unit for sealing and covering the nozzle forming surface of the recording head when the device is in a non-print mode. The capping unit functions as a lid for preventing the ink from drying at the nozzle openings of the recording head. When the nozzle opening or openings are clogged, the capping unit also functions to remove the clogging in a manner that it sucks the ink from the nozzle openings by the utilization of a negative pressure from the suction pump.
The forcible ink sucking operation for removing the clogging is called a cleaning operation. The cleaning operation is performed when the recording device have been left not used for a long time and starts again its operation, when the user recognizes a printing failure and operates a cleaning switch, and in other situations. In the cleaning operation, a negative pressure is applied from the suction pump to the nozzle forming surface of the recording head, and the ink is sucked therefrom and discharged into the capping unit. Then, the nozzle forming surface is wiped out with a wiping member made of rubber or the like.
In the related recording device, the capping unit is mounted on a drive unit which is capable of crawling on the nozzle forming surface of the recording head by the utilization of a drive force of the carriage when it moves to the home position. The wiping member is mounted on a horizontal drive unit which moves to and from a movement region of the recording head within which the recording head is moved with the movement of the carriage. With the cleaning operation, a cleaning sequence is executed in which the wiping member wipes out the nozzle forming surface of the recording head while rubbing lightly the surface.
Thus, in the related recording device, separate drive units are used; the vertical drive unit for vertically driving the capping unit and the horizontal drive units for driving the recording head within the movement region in the horizontal direction. This fact entails the increase of device size and cost to manufacture.
Many recording devices of this type are designed such that the power generated by a sheet feeding motor, which feeds a recording sheet in a direction orthogonal to the moving direction of the carriage, is utilized for the drive force necessary for the horizontal drive unit for driving the wiping member for its forward and backward movement, and the drive force necessary for the suction pump.
To this end, a friction clutch is incorporated into the drive unit for driving the wiping member. In an initial stage of the rotation of the sheet feeding motor to one direction, the wiping member is advanced to the head movement region and is put to a set state. In an initial stage of the rotation of the motor to the other direction, the wiping member is retracted from the head movement region and is put to a reset state through the friction clutch.
Accordingly, if, as the result of the cleaning operation, the friction clutch is smeared with waste ink sucked from the recording head and waste ink wiped from the nozzle forming surface of the recording head, the normal driving of the wiping member is hindered. Further, if the gear, e.g., a drive gear, for transmitting a drive force to the friction clutch, is smeared with the waste ink, solidified waste ink will excessively increase the load of the sheet feeding motor. This will create more serious problems.
An ink jet recording device with a head cleaning mechanism is proposed in JP-A-10-193629. This head cleaning mechanism is operable without the drive unit for moving the wiping member to and from the recording head in the horizontal direction. In the mechanism, a slider is located adjacent to the home position of the recording head. The cap member and the wiping member are supported on the slider. When the recording head moves to the home position, the slider is moved toward the nozzle forming surface of the recording head in connection with the head movement, and the nozzle forming surface of the recording head is sealed and capped with the cap member.
When the recording head is moved apart from the home position, the slider is moved in such a direction as to separate the slider from the nozzle openings of the head, and the sealing of the nozzle forming surface with the cap member is removed. During the slider moves apart from the nozzle openings, the slider is locked to halt its movement. With the subsequent movement of the recording head, the nozzle forming surface of the recording head is wiped out with the cap member.
In the disclosed technique, when the recording head is moved from the home position to the head movement region, the slider is locked and halts its movement. Accordingly, the nozzle forming surface of the recording head is inevitably wiped out with the wiping member. Therefore, also when a flushing operation for idle ink ejection is performed by applying a drive signal not related to the printing to the recording head, the nozzle forming surface is wiped with the wiping member.
During the wiping operation, the solidified ink sticking to the wiping member comes in sliding contact with the nozzle forming surface. As a result, there is the possibility that the solidified ink damages the nozzle forming surface, and the nozzle openings are clogged with the solidified ink. Further, there is possibility that the wiping operation destroys the ink meniscus at the nozzle openings after the ink meniscus have been restored to good condition through the flushing operation.
Accordingly, an object of the present invention is to provide an ink jet recording device and a method for driving and controlling the same, which solve the problem of the damaging of the nozzle forming surface by the wiping operation and the problem of the hindering of the normal ink ejecting operation by the wiping operation in a manner that the wiping operation by the wiping member is appropriately selected in its execution by the utilization of a mechanical arrangement in which the wiping member is also mounted on a holder on which the cap member is mounted
In order to solve the aforesaid object, the invention is characterized by having the following arrangement.
(1) An inkjet recording device including an inkjet recording head which is mounted on a carriage being reciprocatively movable from a print region to a home position, ejects ink drops in accordance with print data and includes a nozzle forming surface, the ink jet recording device comprising:
capping means which seals up the nozzle forming surface and is capable of sucking and discharging ink from the recording head under a negative pressure received from a suction pump, the capping means including,
a drive unit controlled so as to approach and separate from the nozzle forming surface,
a cap holder mounted on the drive unit,
a cap member which is disposed on the cap holder and is capable of being brought into contact with the nozzle forming surface with a movement of the drive unit for sealing up the nozzle forming surface,
a wiping member which is mounted on the cap holder at a side of the print region and is slidably contactable on the nozzle forming surface, and
a cap retaining member which is selectively moved to and from a moving path of the cap holder and is capable of blocking a movement of the cap holder when the cap holder moves.
(2) The ink jet recording device according to (1), wherein an ink receiving recess is provided between the cap member and the wiping member.
(3) The ink jet recording device according to (2), wherein the ink receiving recess is formed integrally with the cap holder holding the cap member and the wiping member.
(4) The ink jet recording device according to any one of (1) to (3), wherein
the cap holder moves forward toward the nozzle forming surface in conjunction with a movement of the carriage toward the home position, so that the nozzle forming surface is sealed with the cap member,
the cap holder moves backward from the nozzle forming surface in conjunction with the movement of the carriage toward a print region, so that the sealing of said nozzle forming surface by said cap member is removed,
the cap holder is retained by the cap retaining member having advanced to the moving path of the cap holder during the backward movement of the cap holder, and
the wiping member held by the cap holder is brought into sliding contact with the nozzle forming surface in a state that the cap holder is retained.
(5) The ink jet recording device according to (4), wherein
the cap holder receives a drive force of the carriage with the movement of the carriage to the home position and responsively moves in an oblique and upward direction when the carriage is moved forward to the home position,
the cap holder receives the drive force of the carriage with the movement of the carriage toward the print region and responsively moves backward in an oblique and downward direction when the carriage is moved toward the print region, and
the cap holder is stopped moving in downward direction by the cap retaining member having advanced to the moving path of the cap holder during the cap holder moves backward in the oblique and downward direction.
(6) The ink jet recording device according to (4) or (5), wherein
the suction pump performs a sucking operation when the suction pump is rotated in a first direction, and
the cap retaining member advances to the moving path of the cap holder in conjunction with the rotation of the suction pump in the first direction.
(7) The ink jet recording device according to (6), wherein the suction pump is a tube pump which generates a negative pressure when a tube of the tube pump, arcuately disposed, is successively compressed with a roller.
(8) A method for driving and controlling an ink jet recording device including an ink jet recording head which is mounted on a carriage being reciprocatively movable from a print region to a home position, ejects ink drops in accordance with print data and includes a nozzle forming surface, a cap member disposed on a cap holder for sealing up the nozzle forming surface when the cap member comes in contact with the nozzle forming surface, and a wiping member disposed on the cap holder at a side of the print region for wiping the nozzle forming surface when the wiping member is brought into sliding contact with nozzle forming surface, the method comprising the steps of:
sucking and discharging ink from the recording head by applying a negative pressure from a suction pump into the cap member in a state that the nozzle forming surface is sealed with the cap member;
removing the sealing of the nozzle forming surface in conjunction with a movement of the carriage toward the print region, and stopping a downward movement of the cap holder by a cap retaining member having advanced to a moving path of the cap holder; and
bringing the wiping member into sliding contact with the nozzle forming surface in conjunction with a further movement of the carriage to the print region.
In the ink jet recording device employing the driving and controlling method mentioned above, the cap member made of a soft material and the wiping member for wiping the nozzle forming surface are disposed on the cap holder. Accordingly, by using the cap retaining member which advances to the moving path of the cap holder and selectively comes in contact with the cap holder, the wiping member may be located on the moving path of the recording head. Therefore, with progress of the cleaning operation, the ink left on the recording head is wiped out, and hence the nozzle forming surface of the recording head is cleaned.
The wiping member disposed on the cap holder may be retracted when the carriage is moved to the print region in a state that the cap retaining member is retracted from the moving path of the cap holder. Accordingly, after the cap member is filled with ink by flushing process, the recording head may be moved to the print region without performing the wiping operation.
The mechanical arrangement mentioned above needs the cap retaining member which is selectively brought into contact with the cap holder. A function to block the retraction of the cap holder upon occasion is merely required for the cap retaining member. Accordingly, it is extremely simple in construction, when comparing with the conventional drive unit for the wiping member, which includes the friction clutch and others.
(9) An ink jet recording device having an ink jet recording head which is mounted on a reciprocatively movable carriage and ejects ink drops in accordance with print data and includes a nozzle forming surface, the ink jet recording devise comprising:
a head cleaning mechanism located adjacent to a home position of the recording head for cleaning the recording head, the head cleaning mechanism including,
a cap holder being located adjacent to the home position being movable to and from the nozzle forming surface,
a cap member supported on the cap holder and being brought into contact with the nozzle forming surface to seal up the nozzle forming surface,
a wiping member supported on the cap holder and being slidable on the nozzle forming surface to wipe the nozzle forming surface in conjunction with the movement of the cap holder,
an interlocking mechanism for moving the cap holder to and from the nozzle forming surface in conjunction with the movements of the recording head to and from the home position, and causing the capmember to seal up the nozzle forming surface and removing the sealing of said nozzle forming surface,
a suction pump for applying a negative pressure to the cap member so that ink is sucked from the recording head and the sucked ink is discharged outside in a state that the nozzle forming surface is sealed with the cap member, and
a holding mechanism for holding the cap holder at a position where the wiping member comes in sliding contact with the nozzle forming surface when the recording head is moved apart from the home position after the sucking and discharging of ink by the suction pump, so that the nozzle forming surface is wiped by the wiping member and the holding state of the cap holder is removed after the wiping operation.
Accordingly, in the recording device thus constructed, when the recording head is moved to the home position, the cap holder is moved to approach to the nozzle forming surface of the recording head by the interlocking mechanism. As a result, the nozzle forming surface of the recording head is sealed with the cap member. In this state, a negative pressure is applied from the suction pump to the cap member, so that ink is sucked and discharged from the recording head. At this time, the wiping member is held at a position where the wiping member may be brought into sliding contact with the nozzle forming surface of the recording head by the holding mechanism. When the recording head is moved backward from the home position after the sucking and discharging of the ink by the suction pump are performed, the nozzle forming surface of the recording head is wiped with the wiping member. Further, the nozzle forming surface is not wiped by the wiping member in a state that the surface is in a dry. Accordingly, the invention successfully prevents such an unwanted situation that the nozzle forming surface is wiped in a dry state to possibly be damaged.
(10) The ink jet recording device according to (1) or (9), wherein at least one of the cap member and the wiping member is formed on the cap holder by two-color molding.
(11) The ink jet recording device according to any one of (1), (9) and (10), wherein the cap member and the wiping member are made of the same soft material.
(12) The ink jet recording device according to any one of (9) to (11), further comprising a restriction mechanism for restricting a displacement of the cap holder apart from the nozzle forming surface when the nozzle forming surface is being wiped by the wiping member.
According to this, a reliable cleaning of the nozzle forming surface is secured.
(13) The ink jet recording device according to any one of (9) to (12), wherein the interlocking mechanism is provided corresponding to the home position of the carriage, and includes a driven member moved by the carriage and converting means for converting the movement of the driven member into the approaching and separating movements of the cap holder.
According to this, the capping of the nozzle forming surface is easily carried out by use of the driven member and the converting means simple in construction, including cams and others. This contributes to construction simplification.
(14) The ink jet recording device according to (13), wherein the holding mechanism is provided between the driven member and a device frame, and includes locking means for locking the driven member at the approaching position of the cap holder, and removing means for removing the locking state of said driven member with the movement of said carriage.
According to this, where the locking means including an interlacing mechanism is provided, the cleaning and wiping of the nozzle forming surface are reliably carried out with a simple construction.
(15) A method for driving and controlling an ink jet recording device according to any one of claims 9 to 14, wherein
when the recording head is moved to the home position, the cap member is brought into contact with the nozzle forming surface so that the nozzle forming surface is capped with the cap member, in this state, the operation of sucking ink is performed, thereafter, when the recording head is moved apart from the home position, the nozzle forming surface is brought into sliding contact with said wiping member so that a wiping operation is performed, and
a flushing operation of idle ejecting ink drops from the recording head is performed in a state that the recording head is moved to a position just before the home position and the cap member is confronted with the nozzle forming surface without contact, thereafter, the recording head is moved apart from the position just before the home position, without sliding contact between the wiping member and the nozzle forming surface.
Where the driving and controlling method thus arranged is used, when the recording head is moved backward from the position just before the home position after the flushing in which the recording head performs an idle ejection of ink drops, the wiping operation is not performed in which the wiping member slides on the nozzle forming surface. Accordingly, the invention successfully prevents such an unwanted situation that the nozzle forming surface is wiped in a dry state following the flushing mode, thereby to possibly be damaged.